[Elecraft] Testing how loud it is!

[George, W5YR]

Thanks for the suggestion, Ron. No, I just got the K2 (prebuilt, darn it!)
last week so I haven't done any of the suggested mods yet, although some
basic ones had already been installed by the builder.

Unlike the tales I have read, my AF Gain control seems to be behaving well
in terms of noise and zero signal out when fully CCW. I guess that the best
way to describe the effect I notice most is that on a strong signal
increasing the AF Gain raises the signal and noise level proportionally,
like a typical radio. But on weak signals, increasing the gain control
appears NOT to increase the noise level proportionally, but rather at times
hardly seems to increase it very much at all.

I need to drag out the HP 400 and noise generator and get some numerical
data on all this so I can make more sense with a description.

Appreciate the help, Ron.

73/72, George     K2 #489 
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe   
Amateur Radio W5YR -  the Yellow Rose of Texas
In the 57th year and it just keeps getting better!


Ron D'Eau Claire wrote:
> 
> George, W5YR wrote:
> 
> As a new K2 operator, my impression of the AF Gain control is that it
> functions unlike the audio gain control of any receiver that I have ever
> used before - and that is a fairly large number!   <:}
> 
> At times, it seems to progressively increase the signal or noise level
> proportionally with knob setting. At other times, it seems to have far
> less effect, again in terms of audio signal level increase versus knob
> position. I suspect that the actual transfer function of the audio
> system is somewhat dependent upon signal level, which while contrary to
> the usual objective in linear system design and implementation, may not
> be all that bad in the K2 application. My K2 has not had the gain pot
> mod.
> 
> ============================
> 
> Have you done the mod to rewire the volume control, George? In the
> original design, the volume control simply "shorted out" the balanced
> audio inputs to the audio amplifier. That produces an odd transfer
> function as well as the oft-reported problems with a 'scratchy pot'
> because the pot had to have virtually ZERO ohms across it in the "off"
> position. Few pots are really a dead short at minimum, nor do they
> maintain a smooth resistance change as tiny movements are made near
> minimum.
> 
> Your symptoms do sound very odd! But if you haven't done the
> modification to rewire the control, you might like it's action a lot
> better and if the other oddities remain they may be easier to run down.
> 
> Ron AC7AC
> K2 # 1289